It is frequently required to dispense items of particulate matter into batches of known quantity. Examples include dispensing candies, seeds or medicinal pills into bottles, sachets or other containers, sorting rough diamonds into packages or containers of approximately equal number of samples, such as to enable different evaluators to estimate the quality and worth of the whole, or the like.
In some dispensing tasks, the finished container must not contain less than the predetermined number of items. For example, when dispensing certain pills, a full treatment cycle may have to be provided, therefore at least the predetermined number of items must be provided in each container.
On the other hand, the dispensed items may be expensive, so if too many of the containers contain more than the predetermined number of items, it translates to direct loss to the supplier of the items or to the packing organization.
In many dispensing machines, the items are transported along a conveyor, at the end of which they fall or are otherwise collected into containers. Thus, if the items are put onto the conveyor in a single file, then a simple counting or weighting mechanism may provide satisfactory results. However, such a mechanism is inherently slower and therefore enables the dispensing of fewer items than if the items were freely placed on the conveyor without posing such limitations.
Furthermore, some dispensing machines also utilize various barriers for physically preventing items from falling off the conveyor once the desired amount has been reached.
U.S. Pat. No. 5,473,703 to Smith, entitled “Methods and apparatus for controlling the feed rate of a discrete object sorter/counter”, discloses a controller which adjusts the vibrator to oscillate the feed bowl at a predetermined amplitude until the sensor array senses a first object. The controller then adjusts the vibrator to oscillate the feed bowl at a lower amplitude and monitors the sensing of other objects. Time intervals between objects being sensed are monitored and the controller adjusts the vibrator to oscillate the feed bowl at a lower or higher amplitude to maintain a constant feed rate. A count of objects sensed is maintained and compared to a predetermined maximum count. When the count of objects equals a predetermined number less than the maximum count, the controller adjusts the vibrator to oscillate the feed bowl at a lower amplitude to lower the feed rate. When the count of objects equals the maximum count, the controller activates a gate closing the chute.
U.S. Pat. No. 6,659,304 to Geltser et al., entitled “Cassettes for systems which feed, count and dispense discrete objects”, discloses a high capacity cassette for an object counting and dispensing system, that includes, inter alia, a structure which feeds the discrete objects in single file toward an exit hole.
U.S. Pat. No. 6,449,927 to Hebron et al., entitled “Integrated automated drug dispenser method and apparatus”, discloses, inter alia, singulation control, which is a process by which drugs move through a canister in a nearly single-file fashion. Means for singulation control is provided by the width of the acceleration ramp and the dispensing ramp. By providing the proper ramp width, the movement of drugs in other than a nearly single-file fashion is prevented. The proper ramp width may in fact be more than one width and may, for example, be a width that is tapered from a largest width to a smallest width. It may also be preferable to design canisters for specific drugs based on the drug size and shape. The drug size and shape may be used to select a proper ramp width. Singulation control may be aided by maintaining the acceleration ramp and the dispensing ramp surfaces on which drugs move at an angle with respect to horizontal. The angle is selected so that the edge of the ramp surface closest to the center of the canister is above a horizontal plane which intersects the edge of the ramp surface farthest from the center of the canister.
Hebron further discloses that in order to minimize the fill time, the drive frequency is increased slowly until it approaches the maximum detection rate of the sensor. The drug count is a discrete integer count registered in a fixed sampling time. A moving average is used as the basis to predict when the last drug will fall through the sensor. As the drug count approaches the total count, the time to terminate the fill is predicted as a fraction of the sampling time of the counting mechanism. The vibration of the canister or unit-of-use bin by the vibrating dispenser is terminated when the estimated time to terminate is reached. In the expected event that the count is short one or two solid drugs, the drive mechanism is restarted as the last used frequency for a short time pulse, 25 milliseconds to 100 milliseconds, for example. Then the drive mechanism is turned off at least until the next drug count registers. If the count is still short, this process is repeated.
European Patent Application No. 1,852,372 to Ogawa et al., entitled “Vibrating bowl, vibrating bowl feeder, and vacuum deposition apparatus”, discloses, inter alia, a vibrating bowl and the like, which are capable of accurately counting the number of objects to be fed, accurately leading objects one by one to an external place per unit time, and aligning collectivity of objects into a row or tier at an intermediate point on a feed passage by simple alignment means.
U.S. Patent Application Publication No. 2003/022291 2005/0263537 to Gerold et al., entitled “Authomated pill-dispensing apparatus”, discloses, inter alia, a bulk storage unit useful for automatically dispensing solid pills includes a track having a length, an upstream end and a downstream end, the track being adapted to feed pills along its length in a longitudinal direction when the track is vibrated. A storage unit includes a hopper positioned over the track and having an opening for dropping pills onto the upstream end, the storage unit including a door movable between an open position permitting singulated pills to drop off the downstream end and a closed position preventing pills from dropping off the track. The door, when close to the closed position and being moved to the closed position, moving parallel the longitudinal direction so that any pills handing partially off the downstream end are pushed back onto the track as the door comes to rest in the closed position.
U.S. Patent Application Publication No. 2010/0205002 to Chambers, entitled “Automated pill-dispensing apparatus”, discloses, inter alia, that pills advance up a spiraling edge of a vibratory feeding bowl and pass through a singulator. Proceeding in a generally single file manner, each pill falls one by one off an exit edge of the vibratory feeding bowl into an upper portion of a pill dispensing route. As the pills pass through the upper portion, they also pass through the light beams provided by a first and second sensor pairs. Then the pills continue down through a lower portion of the dispensing route, usually a dispensing chute. After passing through the dispensing chute, the pills pass through a dispensing neck and out of the pill dispensing device and into the pill bottle. Once the desired number of pills has been dispensed, the controller signals the vibratory base unit to turn off. Moreover, a pill stop mechanism is activated by the controller to prevent any additional pills located close to the exit edge from falling into the upper portion of the dispensing route.
U.S. Pat. No. 6,253,953 to Ishizuka, entitled “Automatic high-speed pill counting apparatus”, discloses, inter alia, an apparatus comprising a cylindrical pill hopper having a pill exit and a center hole in a base plate; a rotational separative feeder mounted in the cylindrical pill hopper and removably fitted on a shaft borne in the center hole of the base plate, the feeder including an upper diametrically smaller portion and a lower diametrically larger portion having an external diameter approximate to the internal diameter of the lower portion of the pill hopper, a multiplicity of vertically through holes being formed in the outer circumference of the lower diametrically larger portion and allowed to come into alignment with the pill exit for accommodating a plurality of pills vertically, the multiple vertically through holes being enlarged at their lower portions, a ring-shaped slit being formed in such a position in the outer circumference of the lower diametrically larger portion as to accommodate substantially one pill from the bottom; and a pill separating plate mounted on the cylindrical pill hopper above the pill exit and having an inwardly projected tip fitted loosely in the slit. The apparatus can count the pills quickly and accurately while preventing the inner wall of the cylindrical portion of the hopper from becoming dirty and the pills from being soiled or broken.
U.S. Pat. No. 4,382,527 to Lerner, entitled “Article handling system with dispenser”, discloses, inter alia, that in a system for dispensing weighed or counted articles, articles are fed from a supply hopper by a vibratory conveyor to maintain a controlled level of articles in a bowl-shaped feeder hopper. In a weigher embodiment, articles are initially discharged from the feeder hopper through two discharge openings into an accumulator bucket. A weighing unit monitors the weight of articles in the bucket and signals a door to close one of the discharge openings as the weight of articles in the bucket begins to approach a predetermined weight. The weighing unit subsequently signals the feeder hopper drive to slow its feeding action as the weight of articles in the bucket more closely approaches the predetermined weight. The feeder hopper discharge openings are arranged near each other at locations where the door-controlled opening will provide a rapid, bulk feed of articles, while the other opening will provide a single-file trickle feed. In a counter embodiment, a feeder hopper having a single discharge opening is used so that articles can pass single file from the feeder hopper past a counter unit to an accumulator bucket.
Japanese Patent No. 2,132,011 to Kazumi et al., entitled “Granular material discharging device”, discloses, in its published English abstract, improvement of the discharge control precision by selecting the vibration frequency in response to the load change or a feeder based on the measured data of the load and flow speed for each vibration frequency so that the flow speed is made constant in a medicine quantitative discharging device using a vibration feeder. The device includes a central processing unit which selects the relational data among the vibration frequency, load, and flow speed in response to the type of an inputted bulk material, e.g., D1. The optimum frequency corresponding to the present load is selected from the data D1 based on the load signal SL outputted from a weight measuring device, and the AC power source corresponding to the frequency signal is fed to an electromagnetic section via a D/A converting circuit, an integrating circuit, a V/F converting circuit, and a power driving circuit; A vibration feeder is operated at the preset frequency, and the flow speed is made nearly constant. The discharge control precision can be improved according to this constitution.
Some dispensing and packing machines include a counting mechanism for determining the actual number of collected objects. By monitoring objects interrupting the illumination of a light source onto a pixelated array, it is possible to count objects being poured.
Such a mechanism is disclosed, for example, in U.S. Pat. No. 5,768,327 to Pinto et al., entitled “Method and apparatus for optically counting discrete objects”. Pinto describes an object counter including a feeding funnel having a frustroconical section, the narrow end of which is coupled to a substantially vertical feeding channel having a substantially rectangular cross section. A pair of linear optical sensor arrays are arranged along adjacent orthogonal sides of the feeding channel and a corresponding pair of collimated light sources are arranged along the opposite adjacent sides of the feeding channel such that each sensor in each array receives light the corresponding light source. Objects which are placed in the feeding funnel fall into the feeding channel and cast shadows on sensors within the arrays as they pass through the feeding channel. Outputs from each of the two linear optical arrays are processed separately, preferably according to various conservative criteria, and two object counts are thereby obtained. The higher of the two conservative counts is accepted as the accurate count and is displayed on a numeric display. In another embodiment, four sensor arrays and light sources are provided. The third and fourth sensor arrays and corresponding light sources are located downstream of the first and second arrays. The outputs of each of the sensor arrays are processed separately and the highest conservative count is accepted as the accurate count and is displayed on a numeric display.
European Patent No. 1,083,007 to Satoru at al., entitled “Method and apparatus for sorting granular objects with at least two different threshold levels”, discloses, inter alia, a method and system for sorting items in different sizes, wherein granular objects flowing in a continuous form are irradiated by light. The resulting image element signals from a solid-state image device are binarized by a threshold value of a predetermined luminance brightness determined for detecting a defective portion of a granular object of a first level, and the above image element signals are also binarized by a threshold value of a predetermined luminance brightness determined for detecting a defective portion of a second level. The second level is for a tone of color heavier than that of the first level. When a defective image element signal is detected from the binarized image elements, an image element of a defective granular object at the center location is specified and the sorting signal is outputted to act on the center location of the defective granular object corresponding to the image element at the specified center location. A granular object having a heavily colored portion which, even small in size, has influence to the product value can be effectively ejected. Sorting yield is improved by not sorting out the granular objects having a defective portion which is small and only lightly colored thus having no influence to the product value.
There is thus a need in the art for a dispensing apparatus and method, which provide for dispensing a predetermined quantity of items in each group, in an accurate, rapid and efficient manner.